The present invention relates to conveyor systems and more particularly to a take-up device for conveyor belt systems.
Conveyor belt systems are used to convey various commercial products. As shown in FIG. 1, conveyors typically include a frame 1 with a tail pulley 2 and drive sprockets 3 on opposite ends of the frame 1 with a continuous or endless belt 4 that runs around the pulley 2 and sprockets 3 and along the length of the conveyor frame 1. The belt 4 is in the form of a loop with an upper conveying portion 5, which conveys product, and a lower return portion 6 below and generally parallel to the conveying portion 5. Typically, a snub idler 7 is placed along the return portion 6 near the drive sprockets 3 to ensure that the belt 4 properly engages the drive sprockets 3. A certain amount of excess belt is usually provided which is allowed to sag 8 in the return portion 6 between the tail pulley 2 and the snub idler 7. The belt within the sag provides tension in the belt 4 so that the belt 4 properly engages the drive sprockets 3. This arrangement is generally referred to as a catenary take-up.
However, this typical arrangement only allows the conveyor belt system to convey in one direction. Often, it is desirable for a conveyor to be bi-directional or have “jog reverse” capability, which means that the conveyor normally runs in a forward direction but can be manually engaged to run in reverse. As shown in FIG. 2, if a conveyor belt system arranged in a catenary take-up is reversed in direction, the drive sprockets 3 pull the excess belt 4 from the return portion 6 to the conveying portion 5. This causes the belt 4 to wrinkle and disengage from the drive sprockets 3 and potentially cause damage to the belt 4, drive sprockets 3, and other parts of the system. In addition to the excess belt provided, the belt gradually stretches and elongates during operation due to wear and tear and various other conditions, such as temperature or humidity. This only adds to the problem.
Consequently, other conveyor system arrangements, such as a center drive arrangement, are typically used whenever it is necessary for a conveyor system to have bidirectional or jog reverse capability. This arrangement requires that the drive sprockets be placed in the middle of the return portion. It also requires additional take-up pulleys to keep proper tension on the belt, and is much more expensive than the simpler catenary take-up arrangement.
What is then needed is a conveyor system with a catenary take-up arrangement that is bidirectional and/or has jog reverse capability.